During an open house at the Headlands Center for the Arts last year, visitors crowded into the studio of artist Lava Thomas. Thomas is known in the Bay Area for works that deal with personal and cultural memory. In that effort, she employs a range of artistic strategies, from photography to sculpture to site-specific installation. But it was three recent drawings, in varying stages of completion, that were creating the buzz.

Rendered with close attention to detail, they were larger-than-life images of African American women, each holding a numbered card. The women depicted might have been criminals, but each was nicely dressed, as if for church or a meeting of the ladies auxiliary. The faces looked, if anything, more reproachful than accused.

Now, 11 finished pictures from the series are on view at Rena Bransten Gallery, and the title of the exhibition explains explains a great deal. “Mugshot Portraits: Women of the Montgomery Bus Boycott” will be on view through Oct. 27.

It is a stunning presentation, inspiring and discomfiting in equal measure. In a time when monuments to men once thought great are shown to be so much wasted bronze, it is heartening to enter a room that pays tribute to homemakers who became heroes by bearing witness to the injustice of a public bus ride. At the same time, the portraits position us squarely in front of these women, implicating us in their arrests and in the morally decadent society they resisted.

Displayed elsewhere in the gallery are several works Thomas assembled, in what has become a signature move, from altered tambourines. The tactic can be effective, as it is in a current show at di Rosa Center for Contemporary Art in Napa, but it feels more repetitive than thematic here. The new drawings are a big step forward, even as they make use of an ancient medium to reference events more than 60 years past.

As transcriptions of their source photographs, not all the drawings trade in the same uncanny sleight-of-hand. The picture subtitled “Lottie Green Varner,” which boldly claims the cover of a small catalog, might be mistaken in reproduction for a camera image, but “Addie J. Hamerter” has more of the look of an Albrecht Dürer drawing or print, with its gleeful emphasis on texture and line.

Seeing both works in the original is a lesson in artistic technique as conveyor of meaning — even of political argument. A reproduction of the original photograph of Varner is included in the catalog. It is tiny but clear, and the subtle differences in the drawing are telling. The harsh light of the police camera flash, an unflattering hot spot in the photo, becomes a beatific radiance in the drawing, and the washed-out detail of the subject’s knuckles is heightened, giving her the hands of a fighter.

“Addie J. Hamerter” delights in the pleasure of precise depiction, as it celebrates touching details — hair that does what it pleases, full features that bespeak proud heritage.

Thomas’ fine-line shading, myriad parallel marks of varying thickness and length, suggest Old Master engraving technique. It gives the flesh of her figures the look of spun metal. They glow, faintly, suggesting the strength of formed stainless steel.

Even the placement of certain characters within pictures becomes, for Thomas, a communicative element. Such decisions are likely based on faulty framing in the original photos. In her drawings, she could have easily adjusted for the errors. It is proof of her close attention to the accidental metaphors of photography that, instead, figures are dwarfed by their sterile surroundings, shoved to the side, noticed only as evidence.

But if they went unnoticed by those in power as individuals, it hardly mattered in the end. One can be sure that these were women who would not have traded results for recognition — certainly not from the white establishment.

The function of this work is not to bring its subjects to life. Those past lives were surely lived with all the dignity we see in the drawings, but Thomas pictures a quiet courage that is still alive, still needed in the future.